Learning JavaScript? Getting ready for an interview for a developer position? Or maybe you are already actively writing in JS and want a little challenge? This application will help you assess the level of knowledge of this programming language. Your attention is provided with more than four hundred questions of various levels of complexity, covering all the current features of the current JS standard. It doesn’t matter if some questions baffle you - links to documentation and additional materials will help you understand why JavaScript behaves this way. Upgrade your JS skills. Write a good code. Do not stop there.